[en] The CyberKnife (CK) is a new type of system that is capable of frameless and image-guided robotic controlled stereotactic irradiation. We evaluated the accuracy of irradiation position, radiation dose and distribution. The accuracy of irradiation position: We calculated the accuracy of irradiation position using Gaf-chromic film, a cubic phantom and a head-shaped phantom. The accuracy of radiation dose and distribution, and as a result of movement of the patient in treatment: We calculated the accuracy by comparing the dose data of the Treatment Planning System (TPS) and EDR2-film in terms of radiation dose and distribution. The accuracy of irradiation position: The irradiation position errors were 0.31 mm (cubic phantom) and 0.30 mm (head-shaped phantom) on median. The accuracy of dose and distribution: It was excellent regardless of the collimator size or irradiation methods. As a result of movement of the patient during treatment: No effect was observed in the present assessment. The results show that the CK system achieved the same level of accuracy as other devices for stereotactic irradiation. The accuracy of the CK system was satisfactory. (author)